BAGHDAD (Reuters) - Suspected Islamic State bombers assassinated an Iraqi provincial police chief and killed 28 people in an attack on a Kurdish security headquarters on Sunday, a second straight day of mass attacks that killed scores.

The two attacks, in the north of the country and the west, showed the jihadist group’s ability to inflict damage on both the forces of the autonomous Kurdish region and the central government, despite U.S.-led air strikes.

Islamic State claimed responsibility for the suicide bombing of a Kurdish security compound in the north, saying it had sent three foreign bombers: a German, a Saudi and a Turk, according to SITE, a group that monitors jihadi announcements.

Hospital sources said Kurdish “Peshmerga” security forces and civilians were among the 28 killed in the attack in Qara Tappa, a mainly Kurdish town in the north of Diyala province, an ethnically and religiously mixed battleground area.

As many as 90 people were wounded in the attack, which hit an administrative compound of Kurds that control the area.

In the east, a blast killed the chief of police of Anbar province, the vast mainly Sunni region of the Euphrates valley that has been one of the main battlefields between government forces and Islamic State fighters for months.

The police commander, General Ahmad Sadak al-Dulaimi, was on patrol in an area where government forces have fought against Islamic State near a village 15 km west of the provincial capital Ramadi when a blast hit his convoy.

A security source said the attack was a shock because it took place in an area that had seemed to be under government control.

In a separate incident on Sunday, two bombs at a market in Diyala’s provincial capital Baquba kill at least six civilians and wounded 10, a police source said.

Sunday’s attacks came a day after militants killed at least 45 people in bombings in west Baghdad and its rural outskirts.

The United States and its allies are providing air support to help government forces and Kurds in Iraq fight against Islamic State militants who have controlled sections of Anbar province for most of this year and swept through northern Iraq in June.

The group also controls a swathe of Syria and has proclaimed a caliphate on both sides of the frontier, imposing a harsh interpretation of Sunni Islam, beheading and crucifying prisoners and ordering non-Muslims and Shi‘ites to convert or die.

Reporting by Baghdad bureau; Writing by William Maclean and Amena Bakr; Editing by Sami Aboudi and Peter Graff